fix: normalize vreckon output longitude to [-180, 180] range#108
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gaoflow wants to merge 1 commit into
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fix: normalize vreckon output longitude to [-180, 180] range#108gaoflow wants to merge 1 commit into
gaoflow wants to merge 1 commit into
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vreckon() was wrapping lon2 with `% tau`, producing values in [0, 360). This caused wrong results for any starting longitude west of the prime meridian: e.g., lon1=-1.27° yielded lon2=358.74° instead of ~-1.26°. The docstring (added by Joaquim Luis) already stated lon2 should be in [-180, 180]. Fix by changing the normalization to `(lon2 + pi) % tau - pi`, which maps [0, 360) correctly to [-180, 180). Update four test expectations that encoded the old [0, 360) convention, and add a regression test for issue geospace-code#88. Fixes geospace-code#88
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Summary
Fixes #88.
vreckon()wrapped the computed destination longitude withlon2 %= tau, producing values in [0, 360). Any starting longitude west of the prime meridian therefore returned a wrong result — e.g. the example in #88:The comment added by Joaquim Luis already stated: "lon2 is always converted to the [-180 180] interval" — the implementation simply didn't match that intent.
Fix
One-line change in
vincenty.py:Four existing test expectations that encoded the old
[0, 360)behaviour are updated (e.g. west-quadrant output270°→-90°), and a regression test for the exact case in #88 is added.All 396 tests pass (9 skipped for missing optional deps).
Test plan
pytest src/pymap3d/tests/test_vincenty_vreckon.py— 17/17 pass (incl. new regression)pytest src/pymap3d/tests/test_vincenty_dist.py— 16/16 passpytest src/pymap3d/tests/ -q) — 396 passed, 9 skippedThis pull request was prepared with the assistance of AI, under my direction and review.